banjo_viking's profile

New Poster


3 Messages

Mon, Nov 16, 2020 9:00 PM

Paying for 600Mbps, Getting less than half. CM1000 modem + Nighthawk AC1900 router

This issue has already consumer hours of my time and has forced me to get an advanced education in routers and modems that I never wanted. When I stand next to my router on 5G bands, I should be able to get something close to the 600Mbps I am paying for, but I can only get a max of 150-280Mbps (using multiple speed test sites). Not bad, but nowhere near where it should be. When the Xfinity techs plug in their own Gateway modem/router, low and behold they get 450-580. Something is up.


I've done ALL the standard procedures (power cycling, ordering, replacing Cat5 with Cat6, checking power adapters, etc.)


My house is a brand new construction (2020), so I doubt it's a cable. We don't have TV, so there is no cable splitting. Techs confirmed I'm getting "beautiful" signals to the house, and they have no issues with their modem/router, so I have to think it's my modem.


My modem is a recommended model per Xfinity. CM1000 Docsis 3.1. It's speaking fine with the router, which is an R7000 Nighthawk (AC1900). Again, more than capable of handling the speeds. All firmeware is up to date, per the Netgear techs.


Some irregularities I've noticed:


  • The wifi speed is MUCH faster than the Ethernet speed, which sits around 100 or less. I've only tested on one laptop, so there's a chance the modem ethernet port or the laptop ethernet port are capped at 100Mbps, but that seems less likely to me for a CM1000 and a 2017 laptop. The Ethernet speeds are the same whether I'm plugged into the router or directly into the modem.


  • I'm only getting 4 upstream channel bonds. Not sure if I should be getting more.


  • My log keeps throwing a dynamic range window violation code saying my power is too high, which you can confirm below, but it doesn't appear to be a major interruption to service. I've yet to notice dropped internet, only slower internet than I should be getting.


At this point, I'm thinking new modem, new router, or both. But I just bought this setup so I would hate to giveup on it too easily. Any advice would be stupendous. Thanks


Startup Procedure
Acquire Downstream Channel573000000 HzLocked
Connectivity StateOKOperational
Boot StateOKOperational
IP Provisioning ModeHonor MDDIPv6 only

Downstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPowerSNR / MERUnerrored CodewordsCorrectable CodewordsUncorrectable Codewords
1LockedQAM25625573000000 Hz8.2 dBmV40.5 dB527068481123
2LockedQAM25613501000000 Hz9.0 dBmV41.0 dB60886218258
3LockedQAM25614507000000 Hz9.4 dBmV40.9 dB608910191519
4LockedQAM25615513000000 Hz8.9 dBmV40.9 dB60894264250
5LockedQAM25616519000000 Hz8.8 dBmV40.8 dB60897561284
6LockedQAM25617525000000 Hz9.0 dBmV40.7 dB60901251300
7LockedQAM25618531000000 Hz8.8 dBmV40.8 dB609060271024
8LockedQAM25619537000000 Hz8.8 dBmV40.8 dB60908896300
9LockedQAM25620543000000 Hz8.7 dBmV40.7 dB60919582276
10LockedQAM25621549000000 Hz8.2 dBmV40.5 dB609260391024
11LockedQAM25622555000000 Hz8.5 dBmV40.6 dB609295681716
12LockedQAM25623561000000 Hz8.6 dBmV40.6 dB609323992012
13LockedQAM25624567000000 Hz7.9 dBmV40.4 dB60937218270
14LockedQAM2561411000000 Hz8.7 dBmV40.8 dB50828218320
15LockedQAM25626579000000 Hz8.5 dBmV40.5 dB609445621519
16LockedQAM25627585000000 Hz7.8 dBmV40.3 dB609484291123
17LockedQAM25628591000000 Hz8.0 dBmV40.5 dB609707821124
18LockedQAM25629597000000 Hz9.1 dBmV40.6 dB60976095825
19LockedQAM25630603000000 Hz8.2 dBmV40.4 dB60979616529
20LockedQAM25631609000000 Hz7.7 dBmV40.2 dB60983303826
21LockedQAM25632615000000 Hz9.0 dBmV40.3 dB609864481024
22LockedQAM2562417000000 Hz8.4 dBmV40.9 dB50948097330
23LockedQAM2563435000000 Hz8.4 dBmV40.9 dB509621361815
24LockedQAM2564441000000 Hz8.3 dBmV40.9 dB50973413264
25LockedQAM2565453000000 Hz8.8 dBmV41.2 dB50983532726
26LockedQAM2566459000000 Hz8.5 dBmV40.9 dB509966521419
27LockedQAM2567465000000 Hz9.2 dBmV41.0 dB51011301265
28LockedQAM2568471000000 Hz9.2 dBmV41.0 dB51024527267
29LockedQAM2569477000000 Hz8.8 dBmV41.1 dB51033669270
30LockedQAM25610483000000 Hz9.2 dBmV41.1 dB51047600312
31LockedQAM25611489000000 Hz9.6 dBmV41.1 dB51053459925
32LockedQAM25612495000000 Hz8.9 dBmV41.0 dB51058490274

Upstream Bonded Channels
ChannelLock StatusModulationChannel IDFrequencyPower
1LockedATDMA536100000 Hz41.0 dBmV
2LockedATDMA629600000 Hz41.3 dBmV
3LockedATDMA723000000 Hz40.5 dBmV
4LockedATDMA816500000 Hz40.5 dBmV
5Not LockedUnknown00 Hz0.0 dBmV
6Not LockedUnknown00 Hz0.0 dBmV
7Not LockedUnknown00 Hz0.0 dBmV
8Not LockedUnknown00 Hz0.0 dBmV

Downstream OFDM Channels
ChannelLock StatusModulation / Profile IDChannel IDFrequencyPowerSNR / MERActive Subcarrier Number RangeUnerrored CodewordsCorrectable CodewordsUncorrectable Codewords
1Locked0159722000000 Hz9.2 dBmV39.5 dB1246 ~ 28493214687535239930
2Not Locked000 Hz7.6 dBmV0.0 dB0 ~ 4095000

Upstream OFDMA Channels
ChannelLock StatusModulation / Profile IDChannel IDFrequencyPower
1Not LockedUnknown00 Hz0 dBmV
2Not LockedUnknown00 Hz0 dBmV




43 Messages

7 m ago

Have you tried connecting to the modem directly and conducted a speedtest? 

Did you check speeds here?

Also, look at the max possible wifi speeds for various devices


New Poster


3 Messages

7 m ago

Thanks for the reply.


Yes, I've run several speedtests at different times of the day. When I'm plugged directly into the modem, I achieve speeds of 100Mbps or less. Same thing when I'm plugged into the router. When I use Wifi, I can get 150-280Mbps. 


Gold Problem Solver


22.4K Messages

7 m ago

@banjo_viking wrote: ... My log keeps throwing a dynamic range window violation code ...

Please post the complete error log.


You may be able to check the laptop's Ethernet adapter speed by checking its device characteristics. If it's running Windows, you can do that in Device Manager / Network adapters.


New Poster


3 Messages

7 m ago


I think I was able to solve my problem, but I don’t know if I solved it so much as I bypassed it.

I had an extra modem and router that were the same models as the one’s I’ve been struggling with, so I decided to swap them out one by one to see if that made a difference. Changing modems made no difference, but switching out the router did make a small difference—nothing drastic though.

I went to the store and bought a very inexpensive wifi-6 router, and suddenly my WiFi speeds are at full capacity! I’m clocking in now at 580 mbps when I stand next to the router. The hard line speeds are still coming in at 100 and lower, thought, and they did not change across the two modems and three routers. I’m starting to think it has something to do with my computer and not my boxes. I’ll have to try connecting in with a different laptop soon to see if that makes a difference.

Thanks everyone

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